Battery life is a key feature of portable electronic devices, such as Tablet PCs. Presently, voltage regulator (VR) losses are key contributors to total platform power loss, typically contributing in the range of 13-23% to power loss. Tablet platforms may employ a single battery pack to supply power to all the voltage regulators and display subsystems in the platform. For example, a 12.6V battery pack having a format of 3 series×parallel cells, (3S×P) may be used to power a VR that generates 5V as well as a VR that generates 0.75V in the platform (device).
Additionally, the VR power-conversion efficiency is very sensitive to the difference between input and output voltages. The power dissipated P in devices switched with a frequency f, can be expressed as CV2f, where C is the capacitance and V the voltage. Generally, larger differences between input and output voltage in a VR result in more power losses, meaning lower efficiency. Thus, using a single battery pack with high number of series connection, may result in an inefficient system because of significant VR power losses.
In addition, battery powered platforms can experience conduction losses from sense resistors in battery packs and charging circuitry. Typically, battery packs and charging circuitry have duplicate sense resistors, which may afford better protection, but may add to expense (cost and power). It is with respect to these and other considerations that the present improvements have been needed.